The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

*Co-chairs of the subcommittee that prepared this document. Note: The committee acknowledges the contribution of associate member Paul Kelley. ACI encourages the development and appropriate use of new and emerging technologies through the publication of the Emerging Technology Series. This series presents information and recommendations based on available test data, technical reports, limited experience with field applications, and the opinions of committee members. The presented information and recommendations, and their basis, may be less fully developed and tested than those for more mature technologies. This report identifies areas in which information is believed to be less fully developed, and describes research needs. The professional using this document should understand the limitations of this document and exercise judgment as to the appropriate application of this emerging technology.

/pdf/guide-for-the-design-and-construction-of-externally-bonded-3wakai247t.pdf

Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures

The “Building Code Requirements for Structural Concrete” (“Code”) covers the materials, design, and construction of structural concrete used in buildings and where applicable in nonbuilding structures. The Code also covers the strength evaluation of existing concrete structures. Among the subjects covered are: contract documents; inspection; materials; durability requirements; concrete quality, mixing, and placing; formwork; embedded pipes; construction joints; reinforcement details; analysis and design; strength and serviceability; flexural and axial loads; shear and torsion; development and splices of reinforcement; slab systems; walls; footings; precast concrete; composite flexural members; prestressed concrete; shells and folded plate members; strength evaluation of existing structures; provisions for seismic design; structural plain concrete; strut-and-tie modeling in Appendix A; alternative design provisions in Appendix B; alternative load and strength reduction factors in Appendix C; and anchoring to concrete in Appendix D. The quality and testing of materials used in construction are covered by reference to the appropriate ASTM standard specifications. Welding of reinforcement is covered by reference to the appropriate American Welding Society (AWS) standard. Uses of the Code include adoption by reference in general building codes, and earlier editions have been widely used in this manner. The Code is written in a format that allows such reference without change to its language. Therefore, background details or suggestions for carrying out the requirements or intent of the Code portion cannot be included. The Commentary is provided for this purpose. Some of the considerations of the committee in developing the Code portion are discussed within the Commentary, with emphasis given to the explanation of new or revised provisions. Much of the research data referenced in preparing the Code is cited for the user desiring to study individual questions in greater detail. Other documents that provide suggestions for carrying out the requirements of the Code are also cited.

"building code requirements for structural concrete (aci 318-11) and commentary"

A review on the utilization of fly ash

Thank you for downloading properties of concrete. As you may know, people have look hundreds times for their chosen readings like this properties of concrete, but end up in malicious downloads. Rather than reading a good book with a cup of coffee in the afternoon, instead they juggled with some malicious virus inside their computer. properties of concrete is available in our digital library an online access to it is set as public so you can download it instantly. Our digital library hosts in multiple locations, allowing you to get the most less latency time to download any of our books like this one. Merely said, the properties of concrete is universally compatible with any devices to read.

Properties Of Concrete

The shrinkage behavior of cementitious materials mixed with seawater is investigated. Cement mortar mixtures were prepared with two water-to-cementitious materials ratios (w/cm = 0.36 and 0.45), two binder compositions (namely, ordinary portland cement (OPC) and OPC with 20 % fly ash replacement), and two types of water (tap water and seawater). The autogenous and drying shrinkage behavior of these mixtures are examined using ASTM standard test methods for 65 days. The use of seawater as mixing water increased the autogenous shrinkage. At w/cm 0.36, the ultimate autogenous shrinkage increased from 213 μs in the mixture with tap water to 387 μs in the mixture with seawater; the corresponding values were 149 and 314 μs, respectively, for mixtures with w/cm 0.45. An acceleration of the cement hydration at early ages caused by the seawater is identified as the cause of the increase in autogenous shrinkage in mixtures with seawater. At w/cm 0.36, seawater did not have a strong effect on the drying shrinkage, and tested mixtures had ultimate drying shrinkage values between 543 and 663 μs. At w/cm 0.45, in mixtures without fly ash, ultimate drying shrinkage increased from 838 μs in the mixture with tap water to 1,027 μs in the mixture with seawater. In mixtures with fly ash, the ultimate drying shrinkage increased from 738 μs in the mixture with tap water to 1,370 μs in the mixture with seawater. The drastic increase in the drying shrinkage in mixtures containing fly ash and seawater at w/cm 0.45 seems to be due to changes in mass loss behavior and the development of a finer pore size distribution. In applications where drying shrinkage may be a concern, the use of fly ash in seawater-mixed concrete could be problematic and lead to increased cracking risk. While the trends observed here will also hold in concrete, quantifying drying shrinkage and cracking of concrete based on the drying shrinkage of mortar mixtures is complex and depends on many other factors.

Shrinkage Behavior of Cementitious Mortars Mixed with Seawater

The use of Fiber Reinforced Polymer wrapping technique has been extensively studied; in particular, the behavior of confined elements of circular cross-sections subjected to pure axial loads has been studied. However, the available models are based on small-scale specimens. Limited studies are found for the cases of prismatic members, especially on large-size ones. To analyze the behavior of axially loaded large-size Reinforced Concrete (RC) columns confined by means of Carbon FRP (CFRP) wrapping, a test matrix was designed to investigate the effect of different variables, such as the geometry of the specimen (circular, square, and rectangular), the area aspect ratio, the side aspect ratio, and a heightto-width aspect ratio. A total of 22 specimens were divided into six series of three specimens each and two series of two specimens. The largest column tested had a cross-sectional area of 0.8 m 2 (9 ft 2 ) and the smallest one an area of 0.1 m 2 (1 ft 2 ). The experimental results are compared and contrasted with current available data on reinforced concrete specimens with one minimum dimension of the cross-section of 300 mm (12 in). This evaluation allowed concluding and confirming that among circular and square specimens of the same cross-sectional area, the confinement effect of the FRP is less effective for the latter. It was observed that within specimens of circular and prismatic cross-sections with size-aspect-ratio less or equal than 2.0, the size effect could be negligible.

Large-size reinforced concrete columns strengthened with carbon frp: experimental evaluation

Over 40% of the bridges in the USA need repair or replacement. The use of near-surface mounted (NSP) fibre-reinforced polymer (FRP) for repairing reinforced concrete (RC) structures is described. The technique involves embedding a bar into a groove half-filled with epoxy paste. Demonstration of the technique by the University of Missouri-Rolla on a bridge on Martin Springs Outer Road, Phelps County, Missouri is described. Load restrictions were placed on the bridge in 1985 due to a lack of transverse reinforcing steel. Details are given of the strengthening process to provide the necessary transverse reinforcement and of the approximate costs. The bridge will be field-tested elastically before and after strengthening.

Near-surface mounted FRP Reinforcement: application of an emerging technology

A 90,000 square meter, three-story, precast concrete parking garage in Pittsburgh, PA was strengthened in order to address concerns regarding distress in the double tee beams supporting each elevated floor. Initially, the distress was manifest in inclined cracks forming at the reentrant corner of the dapped ends. During an independent load test of sample tees, additional cracks at approximately 1.5 m from the dapped end formed and became so severe that, at roughly 75% of the design load, the tees were deemed to have failed. This failure condition resulted in an effort to strengthen the ends of the tees in the garage for shear and flexure. In assessing various strengthening alternatives, externally bonded carbon fiber reinforced polymer (FRP) reinforcement was determined to be the most cost effective, the least disruptive to the operation of the parking garage, and virtually unnoticeable once the installation was complete. A load test of several tees after the installation of the FRP reinforcement demonstrated that the retrofitted tees could support loads over 100% of the design load. This paper presents the details of the design, specification, installation, and testing of the FRP strengthening system for this large retrofit project.

Strengthening dapped ends of precast double tees with externally bonded FRP reinforcement

Extensive experimentation in pavement construction has been conducted using steel fiber reinforced concrete (SFRC). Although SFRC has demonstrated outstanding mechanical properties, its commercial application has been limited because of high cost. Cost savings could be realized for paving projects constructed with the emerging roller compacted concrete (RCC) technology. In particular, pavement thickness reduction due to the inclusion of fibers in RCC can allow single-lift construction where two lifts of unreinforced concrete would be required. Alternatively, for two or more lifts, SFRC can be confined to the most stressed layer(s). This paper presents compression and split tension results of laboratory cylinders and field cores reinforced with different types of steel fiber in various percentages. The concrete matrix contained fly ash, either Class F (used as a filler) or Class C (used as a binder). Fiber inclusion disturbed the consolidation of laboratory specimens, whereas field cores did not indicate any loss of density or compressive strength. Post-cracking characteristics were greatly enhanced by fibers with ultimate strength and toughness indexes derived from stress-strain curves for split tension. Sample design calculations compare the preliminary pavement thickness of unreinforced and fiber reinforced RCC with cost estimates for each.

Antonio Nanni

Papers

Shrinkage Behavior of Cementitious Mortars Mixed with Seawater

Large-size reinforced concrete columns strengthened with carbon frp: experimental evaluation

Near-surface mounted FRP Reinforcement: application of an emerging technology

Strengthening dapped ends of precast double tees with externally bonded FRP reinforcement

Properties and design of fiber reinforced roller compacted concrete